Method and apparatus for burning clayware



May 10, 1927 1,628,273

- W.. D. RICHARDSON METHOD AND APPARATUS FOR BURNING CLAYWARE Filed m 2-5. 1924 4 Sheets-Sheet 1 A TTORNEY.

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I 1,628273 W. D. RICHARDSON METHOD AND APPARATUS FOR BURNING CLAYWARE Filed May 23. 1924 4 Sheets-Sheet 2 A TTORNEY.

4 Sheets-Sheet 3 an Phi" lllllllv V INVENTOR.

ATTORNEY.

I Ma 92 I y 1 7 w. o. RICHARDSON METHOD AND APPARATUS FOR BURNING CLAYWARE Filed May 23. 1924 Patented May 10, 1927.

PATENT OFFICE.

WILLARD D. 'RICHABDSON, OF. COLUMBUS, OHIO.

METHOD AND APPARATUS FOR BURNING CLAYWARE.

Application filed May 23,

My invention relates to method and apparatus for burningclay Wire, and pertains to the distribution of heat in the burning of clay Ware in tunnel kilns. It is particularly applicable tothe burning of sanitary Ware, terracotta, brick and other heavy clay products.

Inthe past, in the burning of the class of Ware referred to, it=has been the practice to place the Wareupon cars and then pass the Ware and cars through the tunnel,

the hot gases from the furnace passing over and through the top and sides of the tunnel in the space nece sarily allowed between the ware on the cars and the crown and the sides of the tunnel, since the draft, induced by a fan at or near the end of the tunnel, is necessarily longitudinal; or the' combustion chambers have been independent of the tunnel and the were on the cars heated by radiation.

In burning clayware in-thistype of tun-- ncl kiln, the Ware upon the outer and top parts of the setting is burnedto a' different r degree than the Ware near the interior of the setting, With the result 'that a large amount of the burned Ware isdefective either from overburning in the top and outer portion of the setting or from under-burning in the central bottom portion. Various methods and means have been utilized in an effortto overcome this objectionable feature of tunnel kilns, some of Which have included attempts to induce cross drafts 'in a zigzag path from one side ot the tunnel to the other, or from the top of the tunnel tothe bottom, obstructing the longitudinal draft in the tunnel by mcans of various forms of baflles. Some of these methods have improved the efficiency of heating some parts ofthe Ware on the cars but such methods have been either impractical or inadequate, or both, for the reason that the Ware in the center of the setting, especially near the bottom, is not burned to the same degree of hardness as the ware in the outer portions ofthe cars.

My invention has to do prin'iarily' with the method of first preheating the Ware in the central bottom portion of the setting to a greaterextent than the Ware at the top and sides of the setting and then heating the were in the top and sides of the setting 1924. Serial No. 715,325.

to counterbalance the preheating'of the Ware 1n the central bottom portion of the setting to effect an even'deg'ree of burning of the vvare throughout eve'ry'portion ofthe .sett1ng. This novel method of preheating and treat ng clay Ware is accomplished bythe provislon of a tunnel kilnwhich is divided lnto separate compartments, and the provisron of a novel car structure, in combination With the tunnel kiln compartments, forcontrollingthe distribution ofgases and the heat in the various compartments.

One of the objects of my invention is the provision ofa tunnel kiln having a firing compartment, preheating compartments, and means carried by one of the Ware-carrying cars in each compartment for separating the firing and the preheating compartments Wherebythe heated products of combustion will contact first with the sidesandtop of the Ware in the firing compartment anawiu then pass to the bottomof'the' cars'inthis compartment andthence through the central bottom portion of. the cars in the preheating compartments in order to initially preheat the are adjacent suc'hbottom central portion of the cars.

Another object of my invention contemplates the provision of a tunnel kiln having preheating, firing andcooling'portions, the firing portion being a separate compartment and the preheating portion being divided into a plurality of supplementary compartments, and means for Wholly or partially separating said supplementary compartments to effect the desired distribution of heat. The result is that the hot gases in the firing portion of the tunnel may be caused topass downwardly through the'clay ware and then pass in a direction towards the preheating compartments. Furthermore, the hot gases in passing through the preheating compartments may be caused to pass through the central bottom portions of the cars to preheat such central portions longitudinal draft tlue throughout the tiring and preheating portions of the tunnel, except where this line is dampered in the first car of the second preheating compartment.

A further object of my invention is the provision of a series of ware-carrying cars having connected draft flues, equally spaced cars having portable partitions and means in the walls of the tunnel kiln cooperating with such spaced partitions whereby the cars may be moved to a position that will prevent the heated gases in the firing compartment from passing; over or through the setting lengthwise of tunnel and cause said gases to pass downwardly through the setting and thence through the longitudinal draft fine in the bottom of the successive cars into the preheating con'ipartments, and in the preheating compartment-s to cause the hot gases to pass through the bottom of the cars.

Another object of my invention has to do with the provision of means for intermittently advancing sections of ware-carrying cars whereby portable partitions carried by certain cars will automatically cooperate with permanent projections constructed in the tunnels to form separate compartments in said tunnels. In this case the separate compartments may be automatically and completely isolated or may be isolated with the exception of the longitudinal draft flue passing through the bottoms of the successive cars.

A further object of my invention has to do with the provision of a tunnel kiln formed in separate compartments and means for exhausting the gases from one compartment by means of conduits and preheating the cars in another compartmentby the radiation of heat from such exhausting conduits. The result is that by exhausting the gases directly from the second compartment, the first compartment may be preheated without the drawing of cold air in through the doors or other inlets.

Various other features of my invention will be apparent as this description progresses and will be brought out in the claims appended hereto. The various objects of my invention are preferably obtained by the structure illustrated in the drawings, where in similar characters of reference designate corresponding parts and wherein:

Figure l is a cross-sectional plan view of the preheating end of the preferred form of my tunnel kiln structure and showing the manner of forn'iing the separate coi'i'ipartments by means of the partitions on the cars cooperating with the projections in the walls of the tunnel and also showing the manner of exhausting the exhaust gases from one compartment and preheating the cars in another compartment by radiation of heat from such exhausting means.

Figure 2 is a cross-sectional plan view of the firing and cooling end of my novel tunnel structure and showing the manner of separating the firing portion from the preheating and cooling portions of the tunnel and also showing the method of utilizing the heat in the cooling portion of the tunnel to preheat the air used for combustion.

F igure 3 is a vertical central longitudinal section of the structure shown in Figure 1 and showing in particular the means for intermittently advancing the car sections whereby the partitions carried by the end ears of each section cooperate with the tunnel walls to form the separate compartments.

Figure 4- is a vertical central longitudiinil section of the structure shown in Figure 2.

Figure 5 is a vertical cross-section taken on line 5-5 of Figures 1 and 3, and showing the pusher pit for advancing the cars and the conduits for conducting the exhaust gases from a preceding compartment and for preheating the ware by adiation in the compartment shown.

Figure 6 is a vertical cross-section taken on line 66 of Figures 1 and 3, and showing the relative arrangement between the cars and the tunnel wheels and also showing the longitudinal draft opening formed in the bottom of the car.

Figure 7 is a vertical cross-section taken on line 77 of Figures 2 and 4 and showing in detail the arrangement of the firing compartment, the combustion bags and the path of the products of combustion passing from the combustion bags to the longitudinal draft fine in the bottom of the cars.

Figure 8 is a vertical cross-section taken on line 8-8 of Figures 2 and 4 and showing the manner of arranging the preheated air conduits in the walls of the cooling tunnel and the blower for forcing the air through such conduits.

Figure 9 is an enlarged detailed view of the firing portion of the tunnel as shown at the left hand end of Figure 2 and showing in detail the manner of conducting the preheated air to the firing zone and the manner of con'ii'iletely ii-iolating the tiring comparlment and the cooling conuaarlment and the manner of connecting the tiring con'iparlmentand one of the preheating comparb ments by means of the longitudinal draft. flue in the bottoms of the cars.

Figure 10 is a longitudinal vertical section of the structure shown in Figure 9 showing the autonnitically actuated damper at the top of the portable partitions for separating the con'ipartments and also showing the successively connected longitudinal draft lines in the bottoms of the cars.

Figure 11 is a fragmentary perspective view, partly cut away, of a bottom of one of my car sections and showing in particular of the'partition and the the longitudinal draft flue in the central bottom portion ofthe car and the distributingfiues leading'to the main draft fine.

Figure 12 is a fragmentary perspective view, partly cut away, of one of tie ears of each section'and .shewing the portable partition'formed upon one end of the car, the self-adjusting damper blocks at the top slidable damper blocks 'for closing the: longitudinal draft flues at the end of the car section.

In the drawings, my tunnel kiln is shown as comprisingfthree main portions, which portions may be designated the preheating portion 1, the firing portion 2 and the cooling portion 3. The tunnel is preferably one continuous structure havingwallswhich are, although of varying cross-section, integrally connected. the three portions, is provided with a floor 4 with tracks, 5 thereon, upon' which tracks are designed to run a series of cars 6.

Asbest shown in Figures 3 and 4, each series of cars 6 constitute a definite number of adjacent cars of definite length. a Each caris provided with a base or platform 7, of suitable material, upon which platform is designed to be piled and suitably arranged,

the ware to beburned. As best shown in Figures 11 and 12,the bottom or platform 7 of each car. is provided with a longitudinal draft" flue 8 which extends longitudinally through the central bottom portion of each car. The bottom of each caris alsopreferably provided with suitabletransverse slots 9, which extend transversely of the car, and which slots extend through the top portion of thelongitudinal draft flue 8. It will be understood that these slots 9m'ay be of any width and are obviously partly, covered by the ware to be burned. It will also be obvious that the size of the slots 9 and the surface covered by the ware upon such slots will restrict and control the gases passing into the flues .8. 1 i

The cars are also provided with suitable flanges 10 extending alongthe sides thereof, and which flanges 10 extend downwardly into suitable sand troughs 11 formed in the walls of the tunnel structure. The cars are also preferably provided with extensions 12 which cooperate withand fit into horizontal grooves 13 formed in the walls of the tunnel.

Each sectionof cars 6 may consist of any number of cars, and as best illustrated in Figures 3 and 4, I have shown each section comprising five cars. illustrated, are designed to be of the normal fiattype as illustrated in Figure 11, while the fifth or end car, which may bedesignated 14, is provided with a vertical parti tion wall 15. Each partition wal1.15 of each end car 14 is providedwith a transverse horizontal slot 16, and which slot is enlarged specially formed damper 20.

The entire tunnel, consisting of.

to suit different ware and with suspended arches 21 Four of these cars, as

adjacent thedraftflue 8 to accommodate a slidablefire'clay tile 17. It will be obvious that the moving of the fire clay tile in o ne dipermit communication between {the draft .flues of the adjacent car sections 6. The top of each partition 15 is provided with a horizontally extending semi-spherical groove groove, as best shown in Figure 12, connects the uneven top surfaces of the partition 15. Designed to fit into this groove 18 isa downwardly extending lug 19 of a In the normal positionofthis dampenas illustrated in Figure 12, one leg is designed to be sup- Port by wall 15, while the other leg of the damper is designed to extend upwardly at an angle to the top surfaces of tl1e wall15.

As best shown in Figures 3 andfl, the

portions 1, 2 and 3 of the tunnel are providedwi th equally spaced flat arches 21, which extend downward ly from the crown 22 of thetunnel. These suspended arches 21 are so spaced that the partition walls 15 of the end cars 14: register. with such suspended arches and the self-adjusting dampers 20, mounted on the top of the arches 15, contact with and are tilted by such suspended arches. It willbe obvious that when the partition wall 15 is in registry with the suspended arch 21' and the damper 20 is tilted contact with the suspended arch 21,

a draft-tight partition wall is formedin the top of the tunnel and a nearly tight partit on on sidesof the, tunnel, Figure 10.

Thepreheating portion of thetunn-el 1 is preferably of a length to accommodate a plurality of suspended arches 21,.which cooperate with the partition walls 15 of the end cars to form a plurality of separate compartments each. of the same length as the firing compartment, said compartments being connected, in the preferred form of my invention, only by the longitudinal draft flues in the bottom central portions of the cars. The firing portion to the tunnel is preferably of a length to accommodate one section of cars 6 but which may be varied different temperatures of burning and is, therefore, provided at each end of the firing portion so as to separate the firing compartment fronithe adjacent compartment of the preheating portion and the adjacent compartment of the cooling portion of the tunnel. As .best shown in Figures 9 and 10. the wall 15cooperating with the susas best shown in pended arch 21at the preheating end of the the lower surface of the top of the portion 3 in the tunnel is designed to accommodate several sections of cars, is preferably continuous and is preferably only provided with one suspended arch 21, which is the arch which separates such cooling compartment from the firing compartment.

The firinpportion of the tunnel, which is best shown in Figures 7, 9 and 10, comprises side walls which cooperate with the car and the ware upon the car and a crown 22, which is symmetrical with the crown eX- tending throughout the tunnel. Disposed alternately along each side of the walls of the firing compartment are a series of furnaces and combustion bags 23. The base of each combustion bag 23 forms the combustion chamber, to which oil or gas is admitted through suitable burners 24 and to which the air for the combustion of fuel is admitted by means of a suitable air duct 25. The air ducts 25 extend along the walls at each side of the firing compartment and connect with each furnace by means of a suitable branch conduit, which is controlled by means of a suitable damper 26. The portion of the combustion bags adjacent the cars is preferably of semi-spherical form and the heated products of combustion pass upwardly through such combustion bags towards the crown of the tunnel and are deflected and drawn downwardly through the ware upon the cars and into the longitudinal draft fiues 8. It is obvious that the height of these combustion bags will vary with the kind of ware to be burned.

The air for the combustion of the fuel in the furnaces is conducted to the ducts 25 by means of suitable heater ducts 27 which extend along the top of the side walls of the cooling section 3, as shown in Figures 2 and 9. These ducts 27 are connected to a suit ible blower 28 whereby the air is forced through the ducts 27, is preheated by the heat given off by the cooling ware in the cooling portion 3 and such preheated air conducted to the furnace ducts 25 where it is combined with the fuel to create combus- (ion.

The products of combustion are drawn downwardly through the ware in the firing compartment p incipally by means of a draft which is induced and set up in the longitudinal draft fine 8. As best shown in Figure 3. the prel'lcating portion is divided into a series of compartments by means of the partitions '15. but the draft fine 8 formed in the has of the cars is con tinuous from the firing compartment to the partition which separates the first and second preheating compartments The second preheating compartment from the entrance 29 of the tunnel is provided with suitable vertical fines 30, and which fines are connected with other vertical flues 31 at the entrance of the tunnel by means of a series of iron pipes 32 which extend along the sides of the first preheating compartment A suitable fan is provided at the entrance of the tunnel and is connected with the vertical tlues 31 whereby a draft will be set up in the pipes 32 and in the second compart" ment and subsequently in the longitudinal draft flue 8 in the base of the cars of the other compartments ahead. Thus, the products of combustion from the furnaces will first contact with the sides and top of the ware on the cars in the firing compartment and will then be drawn downwardly through the ware and into the longitudinal draft flue 8. It will be obvious that the products of combustion will then be drawn through the longitudinal draft flue S in the preheating compartments to heat the ware adjacent the central bottom portion of the cars until such products of combustion reach the end of the second preheating compartment, when such products of combustion will be drawn into the setting of the second compartment and thence through the pipes 32 and then exhausted to the atmosphere. It will further be obvious that by conducting the products of combustion through the pipes 32 in the first preheating compartment, the ware in such compartment will be preheated bv radiation of heat from such pipes 32, which is the proper treatment for green ware, since the strong circulation of heated gases that would otherwise occur in the compartment nearest to the draft pan would be too severe for green ware.

As best shown in Figures 3 and 5, the preheating compartment is provided with a pusher pit This pit is provided with a suitable chain 34 mounted upon suitable sprockets 35. The chain 34 is preferably provided with suitable lugs 36, which are designed to contact with suitable downwardly projecting lusts 37 on the cars 14 of each section. It will thus be obvious that by moving the lug 36 along the length between the sprockets 35. the car sections in each compartment will each be advanced to the next adjacent compartment.

The preheating and firing portions of the tunnel are preferably provided with suitable pilasters 38 on each side of the tunnel. 'lhese pilasters are arranged in a plane with the suspension arches 21' and thus further cooperate with the partitions 15 of the end cars to produce isolated compartments in the tunnel.

In the normal operation of my tunnel kiln. the car sections 6 are moved forwardly, from left to right in Figures 1 to 4 by moving the dogs 36 in the pusher pit. The cars will be moved forward a definite amount until the partition walls 15 on the end cars 14: register with the suspension arches 21 and pilasters 38 along the tunnel. The cars in every compartment will be simultaneously moved for ill) Hill

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ward to the next compartment at intervals determined by the time necessary to properly heat the ware in the firing compartment and thus depending upon the ware being burned, As the ware in the firing compartment is being burned, the products of combastion which initially .heat the ware at the sides and top of the cars to a relatively high degree, are drawn downwardly into: the longitudinal draft flue 8. Referring particularly to Figures3 and 10, the products of combustion will then be drawn through the longitudinal draft flue 8 in the successive preheating compartments by means of the draft induced in the pipes 32 by thefan, wherein the ware which is located adjacent the central bottomportion of the cars will be heated to a relatively high extent com pared to the ware located on the sides and top of the cars in the preheating compartments. When the ware in. the compartment underfire has been brought to the proper heat andthe ware has matured in all por tions of such compartment, the cars in the first or receiving preheating compartment are pushed forward into the second preheating compartment, thus moving the cars for ward in every compartment and also moving the cars in the firing compartment forward into the cooling section 3 of the kiln and pushing out of the kiln an equal number of cars of relatively cool ware.

Before the cars enter thethird compartment of the tunnel kiln, the fire clay. tile 17 is pushed to one side by means ofasuitable bar, as shown in Figure 12. .The tile 17 1n each compartment remainsin this open position until the partition 15 reaches the point which separates the firing compartment from the cooling portion of the kiln. At this point, one side of the kiln, as best shown 1n Figure 9, is provided with a slot 39, through which an iron rod may be inserted to push I ,the tile 17'into. closedposition to completely isolate the two compartments thus separated. When the dampers 20 are moved into positi'onj beneath the suspended arches 21, the bottom of such arches will contact with the uppermost surface of the dampers and thus partially revolve such damper about the groove 18 as an axis. Thus,this.damper;is selfeadjusting when moved into posltion beneath the suspended arches to completely isolate the separated compartments.

It will be seen that I have provided a novel and decidedly simple tunnel kiln for treating and burning clay ware, which is of ample compactand strong construction and well adapted to the equal burning of the ware carried by the cars passing through the kiln. l

It will further be notedthat I have provided a tunnel kiln,

compartments by means of the cars passing through said kiln.

sections of cars are in the preheating end of which is divided into a pluralityof separate.

Thus, the first preheatng compartment is provided with exhausting flues from which heat is radiated to initially preheat all the ware upon the car in such compartment. Furthermore, the ware further preheated by the products of combustion passing through the flue '8, whereby the ware adjacent such flue will be heated to a relatively high extent. Other preheating compartments may be provided whereby the ware adjacent the flue 8 may be heated to a relatively higher extent before passing into the firingcompartment. Itwill thus be seen that I have provided a methodfor initially and generally preheating the ware on the section of cars by radiation, then preheating the ware on the cars by heating the ware adjacent the central lower portion of the cars by the products of combustion and then still further heating such centrally located ware to aihigher extent by the prodcompartment the top and sides of the car have the advantage inheating up.

It will be understood that the preheating,

firing and cooling portions of my tunnel kiln may be of varying lengths and sizes to accommodate various sizes and lengths of car sections and that such portions of the tunnel may be divided up intozany number of separate compartments desired. It will also beinthe second preheating compartment will understood that the ware inthe cooling por-i I tion of. the tunnel may, if desired, be cooled by utilizing an. exhausting fan or by any other standard method. 1

It will be further understood thatthe slots 9, in the platform of the conveying cars, may be varied in size so that more on less gas may be conducted into and through i the longitudinal flue 8 or distributed through theslot-s 9. It will also be obvious that any kind of. fuel may be used in the furnaces in the firing compartmen As illustrated in Figures 1 and3, it will be understood that the fire clay tile 17' in the partitions 15 of-the first and second order that the induced draft set up in the pipes 32 will not draw any cold air from the first preheating compartment.

closed position, in

Furthermore, asshown in Figure 1, a slot40 is formed in one side of the wall between the second and third preheating compartments. to register with the slot16 formed in the end car l4e of each section whereby when each section of cars 6 is moved from the second to the third compartments, the fire clay tile preheating tunnel This slot is positioned 17 can be pushed, by means of a suitable rod, into open position.

Having thus described my invention, what I claim is:

1. The method of burning clay ware in a tunnel kiln which comprises heating that portion of the ware adjacent the central bottom portion or the conveying units to a relatively high degree and then subjecting the surrounding ware to a relatively high degree of heat.

2. The method of burning clay Ware in a tunnel kiln which comprises heating that portion of the ware adjacent the central bottom portion of the conveying units to a relatively high degree in one portion of the tunnel and then subjecting the surrounding ware to a relatively high degree of heat in another portion of the tunnel 3. The method of burning clay ware in tunnel kilns containing preheating and firing compartments which comprises distributing hot gases around and through the ware in the firing compartment and localizing said gases to heat the bottom central portion of the ware in the preheating compartment.

4. The method of burning clay ware in tunnel kilns containing compartments which comprises distributing hot gases around and through the ware in one compartment and localizing said gases to heat a portion of the ware in another compartment to a relatively high degree.

5. The method of burning clay ware in tunnel kilns containing compartments which comprises distributing hot gases around the ware in one compartment, localizing said gases to heat a portion of the ware in another compartment to a relatively high degree and preheating the ware in another compartment by the radiation of heat from a heated surface.

6. The method of burning clay ware in tunnel kilns containing compartments which comprises distributing hot gases around the ware in one compartment, localizing said gases to heat a portion of the ware in another compartment to a relatively high degree, exhausting said gases and then preheating the ware in another compartment by radiation of heat from said exhausted gases.

7. The method of burning clay ware in tunnel kilns which comprises sealing one portion of the kiln from another portion and passing gases through a portion of the seal.

8. The method of burning clay ware in tunnel kilns which comprises forming compartments, sealing one portion of the kiln from another portion and passing gases through a portion of the seal.

9. The method of burning clay ware in tunnel kilns which comprises forming compartments, by the ware carrying units, seal-- ing one portion of the kiln from another portion and passing gases through a portion of the seal.

10. The method of burning clay ware in tunnel kilns which comprises automatically sealing one portion of the kiln from another portion and passing gases through a portion of the seal.

11. The method of burning clay ware in tunnel kilns which comprises forming compartments, automatically sealing one portion of the kiln from another portion and passing gases through a portion of the seal.

12. The method of burning clay ware in tunnel kilns which comprises forming compartments, by the ware-carrying units, automatically sealing one portion of the kiln from another portion and passing gases through a portion of the seal.

13. The method of burning ware in tunnel kilns which comprises heating air by radiation of heat from cooling units, combining such preheated air with fuel to produce combustion, and localizing the products of combustion to heat the central bottom portion of the ware on the conveying units.

14. In combination with a tunnel kiln of means on the conveying units for sealing the passage of gases above the ware and means for controlling the passage of gases through successive conveying units. 7

15. In combination with a tunnel kiln of means on the conveying units for automatically sealing the passage of gases above the ware and means for controlling the passage of gases through successive conveying units.

16. In combination with a tunnel kiln of means on the conveying units for dividing the tunnel into compartments, sealing the passage of gases above the ware and means for controlling the passage of gases through successive conveying units in successive compartments.

17. In combination with a tunnel kiln of means on the conveying units for automatically dividing the tunnel into compartments, sealing the passage of gases above the ware and means for controlling the passage of gases through successive conveying units in successive compartments.

18. In combination with a tunnel kiln of means for conveying ware through said tunnel and tilting means on said conveying means for separating the conveying means.

19. In combination with a tunnel kiln of periodically operated means for conveying ware through said tunnel and tilting means on said conveying means for separating the conveying means.

20. In combination with a tunnel kiln of means for conveying ware through said tunnel and tilting self-adjusting means on said conyeying means for separating the conveymg means.

21. In combination with a tunnel kiln of means for conveying ware through said tunnel and self-adjusting means on said conveying means for dividing the tunnel into separate compartments.

22. In combination with a tunnel kiln of means for conveying ware through said tunnel and tilting means for separating the conveying means.

23. In combination with a tunnel kiln of means for conveying Ware through said tunnel and tilting self-adjusting means for separating the conveying means. 7

24. In combination with a tunnel kiln of periodically operated means for conveying Ware through said tunnel and tilting selfadjusting means for separating the conveying means.

25. In combination'with a tunnel kiln of periodically operated means for conveying Ware through said tunnel and tilting selfadjusting means on said conveying means for separating the conveying means.

26. A tunnel kiln divisible into compartments and means for forcing the gases through the central bottom portion of the ware throughout the length of one of the compartments.

27. A tunnel kiln divisible into compart ments comprising means for controlling the heating of gases by radiation of heat from the Ware and the horizontal passage of gases to heat portions of the Ware.

28. A tunnel kiln divisible into compartments comprising means for controlling the heating of gases by radiation of heat from the ware and the horizontal passage of gases through successive compartments to heat portions of the ware first by convection and then by radiation.

29. A tunnel kiln divisible into compartments comprising means for controlling the heating of gases by radiation of heat from the ware, the passage of hot gases downwardly through the ware and then through a horizontal passage to heat portions of the ware.

30. A tunnel kiln divisible into compartments comprising means for controlling the passage of hot gases downwardly through the ware and the horizontal passage of gases to heat portions of the Ware.

31. A tunnel kiln divisible into compartments comprising means for controlling the passage of hot gases downwardly through the ware and the horizontal passage of gases through successive compartments to heat portions of the ware.

32. A continuous car-tunnel kiln having the preheating portion divided into compartments of the same length as the firing compartment by means of flat arches suspended below the crown, pilasters on the side walls of the tunnel and a partition built up on one end of the last car 111 each compartment.

33. A continuous car-tunnel kiln having portable partition Walls on the cars and tilting, self-adjusting damper blocks on top of said partition walls.

34. A continuous car-tunnel kiln divided into separate compartments by means of flat arches suspended from the crown, pilasters on the side walls, partition walls on one end on certain of the cars on which the ware to be burned is set, and tilting, self-adjusting refractory dampers on top of the portable partitions, registering with the suspended arches.

35. The method of burning ware in tunnel kilns which comprises sealing one portion of the kiln from another portion and heating the Ware in said sealed portion by radiation.

In testimony whereof I affix my signature.

WILLARD D. RICHARDSON. 

